NOAA Finds PM and Black Carbon in Air near Gulf Spill

Jul 22, 2010

National Oceanic and Atmospheric Administration scientists said their data on air quality measurements taken in June in the vicinity of the Deepwater Horizon/BP oil spill area are consistent with those of the U.S. Environmental Protection Agency and the Occupational Safety & Healthy Administration.

The NOAA report summarizes the levels of nearly 100 air pollutants measured with sophisticated air sampling instruments onboard a WP-3D research aircraft.

Scientists found common air pollutants, such as ozone, nitrogen oxides and carbon monoxide, in amounts typical of urban areas in U.S. cities. However, 15 to 70 kilometers downwind from the oil spill, concentrations of certain hydrocarbons were much higher than found in typical polluted air. Particulate matter downwind of the oil slick was comparable to concentrations in moderately polluted urban air, but the particles were almost entirely organic material, as opposed to those typically found in urban particulate matter. Scientists also measured large amounts of black carbon in smoke from a controlled burn of crude oil on the water.

“Data from the NOAA flights are providing an important detailed and independent set of air quality data to assess air quality risks of workers at sea and the public ashore,” said A. R. Ravishankara, director of the Chemical Sciences Division of NOAA’s Earth System Research Laboratory, who led the science team.

NOAA scientists measured the air pollutants in four areas, including in the immediate vicinity of the spill, downwind from the spill, and along the Mississippi, Alabama and Florida coastlines. They also measured “background” air in an area far from the spill to serve as a control sample. In analyzing the levels of the pollutants, scientists compared them to typical concentrations of a polluted U.S. urban area.

The near-shore measurements, 30 to 40 kilometers from shore, showed pollution concentrations generally lower than those typically found in urban areas. The background air was relatively free of pollution from the oil spill.

The report offers a highly detailed snapshot of the concentrations of hydrocarbons and other organic chemicals, particulate matter, ozone, carbon monoxide, nitrogen dioxide, peroxyacetyl nitrate and a host of other air pollutants in the Gulf in early June. Measurements were taken from as low as 60 meters above sea level and up to 1,000 meters above sea level, with most flight tracks being about 150 meters above the Gulf.